// let age: number = 19

// age = 'hello'

let age: number = 19

console.log(age)

let num: number = 10
let msg: string = 'hello ts'
let flag: boolean = true
let isNull: null = null

let isUndefined: undefined = undefined

console.log(num)
console.log(msg)
console.log(flag)
console.log(isNull)
console.log(isUndefined)
